Nitrogen-doped carbon microspheres derived from oatmeal as high capacity and superior long life anode material for sodium ion battery

Nitrogen-doped carbon microspheres (NCSs) derived from oatmeal are employed as anodes for sodium ion batteries (SIBs). Their morphology, structure and electrochemical performance are characterized by field emission scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, nitrogen adsorption-desorption isotherms, galvanostatic charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The results show that NCSs treated at 500 °C exhibit a high maximum charge capacity of 336 mA h g^-1 after 50 cycles at a current density of 50 mA g^-1 and even at a high current density of 10 A g^-1 within 70 s charging time, a capacity of 104 mA h g^-1 is maintained after 12500 cycles without obvious decay. The high capacity, excellent rate performance, long life cycling and ultrafast rechargeable ability enable the NCSs to be a promising candidate for practical SIBs.